Synthesis and characterization of a novel microporous aluminophosphate AIP0,-JDF (ZAlPO, HOCH2CH2NH2)from alcohol systems Qiuming Gao,"" Shougui Li,"Ruren Xu*" and Yong Yueb "Key Laboratory of Inorganic Hydrothermal Synthesis, Jilin University, Changchun 130023, P.R. China Wuhan Institute of Physics, the Chinese Academy of Science, Wuhan, P.R. China The synthesis of a novel aluminophosphate microporous compound AlP0,-JDF (where J means Jilin University and DF is Davy Faraday Laboratory) containing organic amine in the presence of the template HOCH,CH,NH, from predominantly non- aqueous media is described. Chemical and elemental analyses disclosed its idealized formula as 2AlP04 -HOCH2CH,NH,. AlP0,-JDF has been characterized by X-ray powder diffraction (XRD), IR spectroscopy, scanning electron microscopy (SEM), differential thermal analysis (DTA) and thermogravimetry (TG), and magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy.Scientists at the Union Carbide Corporation have synthesized a series of alumin~phosphates'-~ (designated AlPO,-n with n representing various structures), and the syntheses and struc- tural determinations of aluminophosphates and aluminoarsen- ates, etc., with frameworks as open as those of AlP04-n, have been reported. Some of these compounds are isostructural with known zeolites or other molecular sieves, e.g. AlP04-20 is the analogue of sodalite, A1Po4-24 is the analogue of analcime, A1Po4-37is the analogue of faujasite, A1P04-42 is the analogue of Na-A, CoA1P04-47 is the analogue of chabazite and AlP04- 17 is the analogue of eri~nite.~-" A large number of these compounds have been synthesized from aqueous systems thus far, and only a few of them are synthesized from non-aqueous systems." Here, we report the synthesis of a novel microporous aluminophosphate, AlP0,-JDF, the analogue of AlAs0,-1, from predominently non-aqueous media in the presence of EAN (EAN =ethanolamine) amine templating agents. Experimental AlP0,-JDF was synthesized from a predominantly non-aque- ous system.Aluminium triisopropoxide (Pr'O),Al and phos- phoric acid (85 mass% H3PO4) were used as the aluminium and phosphorus sources, respectively. (PI-'O)~AI was firstly stirred with HOCH,CH,OH, then EAN was added with stirring, and phosphoric acid was lastly added dropwise.The whole mixture was stirred until it became homogeneous. The final gel was transferred to an autoclave and heated under autogenous pressure. The crystalline product was filtered, washed with distilled water, and dried at ambient temperature. The typical gel molar compositions and crystallization con- ditions are shown in Table 1. Elemental analysis was performed on a Perkin-Elmer 240C element analyser. X-Ray powder diffraction data were collected on a Rigaku D/MAX I11 + diffractometer with Ni-filtered Cu- Ka radiation (A= 1.5418 A). The sample was scanned from 4 to 40" (28) at a scan speed of 0.5" min-'. The IR measurements were carried out on a Nicolet 5DX FTIR spectrometer using KBr pellets.A Perkin-Elmer DTA 1700 differential thermal analyser was used to obtain the differential thermal analysis (DTA) data, and a Perkin-Elmer TGA 7 thermogravimetric analyser was used to obtain the thermogravimetry (TG) curves in an air atmosphere. The heating rate was 20 "C min-'. 27Al MAS NMR spectra were recorded on a Varian XL-200 spec- trometer with a magnetic field strength of 4.7 T. The spinning rates were 3 kHz. The single-pulse excitation technique was applied and the spectra were obtained at 52.1 MHz. Other parameters were: pulse width, 0.5 ps; recycle delay, 10 s; number of transients, 1000. The chemical shifts were relative to the external standard A1(N03)3 aqueous solution. 13C and 31P MAS NMR spectra were measured on a Bruker MSL-400 spectrometer (9.4 T).The spinning rates were 5 and 6 kHz, respectively. The cross-polarization technique was applied. The contact time was 5.0ms and the scan number 1000 with a recycle delay of 14 s. The relaxation delays of 27Al, 31P and 13C were sufficiently long that the spectra were quantitatively reliable. The chemical shifts were relative to SiMe, and H3PO4 (85 mass %) respectively. Results and Discussion Formation and composition AlP0,-JDF or AlAsO,-l forms only in the presence of EAN as a template (the former comes from the alcohol media and the latter comes from the water media)." The preferred tem- perature for crystallization of AlP0,-JDF is 180°C. A large amount of AlP0,-tridymite forms and a little AlP0,-JDF is found >2OO"C. When the temperature is below 150"C, only an amorphous phase exists. The alcohol solvent may be ethylene glycol (EG), propane-1,2-diol ( 1,2-PG), propane-1,3- diol ( 1,3-PG), butane-1,4-diol ( 1,4-BG), triethylene glycol (TEG) or hexanol (HexOH).Chemical analysis and EDAX give rise to a P/A1 value of 1.0for the product. Element analysis indicates that the material contains 4.13 mass% N, 8.38 C, and 2.86 H with molar ratio N :C :H =0.42: 1.00:4.09. TG shows that the mass loss is 24.7 mass%. The empirical composition calculated on the basis of the above data is 2.00(AlP04)* 1.03( HOCH,CH,NH,), which can be normalized to 2AlP04 -HOCH,CH,NH,!. This formula corresponds to that of A1As04-1, the formula of which is 2A1AsO4 .HOCH,CH,NH,.X-Ray powder diffraction and SEM analyses The XRD pattern of the as-synthesized AlP0,-JDF is shown in Fig. 1. It is seen that the peak positions are essentially identical with those for the pattern of AlAsO,-l, except for the difference of peak inten~ities.'~ This indicates that AlP0,-JDF is the analogue of A1AsO4-1, which is orthorhombic, and whose space group is Pcab. SEM (Fig. 2) shows that the particles are aggregates of numerous small crystals. The average particle and crystal sizes are ca. 6 pm and 0.5 pm, respectively. The particles are homo- J. Muter. Chem., 1996, 6(7), 1207-1210 1207 Table 1 The typical gel compositions and crystallization conditions for AlP0,-JDF moles P,05" moles EAN moles organic solvent moles H,O ETN t/days ~ 2.4 13.5 60 EG 12 0.790 5 2.4 14.0 44 EG 12 0.790 7 1.8 6.8 34 1,3-PG 9 0.747 7 1.8 7.0 45 1,3-PG 9 0.747 14 1.8 6.8 33 1,2-PG 9 0.722 22 2.4 13.5 30 TEG 12 0.7 13 24 1.8 6.8 28 1,4-BG 9 0.704 25 1.8 6.7 20 HexOH 9 0.559 30 Molar content of A1,0,, 1.0; reaction temperature, 180°C.Expenmental polar constants (ref. 22). geneous and the crystal shape is similar, indicating that the as-synthesized solid is a pure phase. IR analysis The absorption bands of the skeleton of the product are at 1181, 1096, 1025, 709, 681, 632, 562 and 534crn-l, which are similar to those of AlAs0,-1 (Fig. 3). According to the frame- work vibration models of A1P04-n,14 the IR absorption spec- trum of A1P04-JDF can be assigned as follows: 1181, 1096 and 1025 cm-l are attributable to asymmetric stretching vibrations of PO4; 709, 681 and 632 cm-' are associated with symmetric stretching vibrations of PO4; 562 and 534 cm-I are assigned to the P-0 vibration (Table 2).Comparing the two IR spectra for AlP0,-JDF and AlA~0,-1,'~ we find that the 111111 10 20 30 40 Fig. 1 XRD patterns of AIP0,-JDF (a) and AlAs0,-1 (b) 1 I I I Y I 1 4OOO.O 3200.0 uoO.0 1900.0 1500.0 1100.0 m.0 660.0 400.0 wavenumber/cm-1 Fig. 3 IR spectra of A1As04-1 (a) and AlP0,-JDF (b) Table 2 Assignment of the IR bonds of the AlP0,-JDF skeleton crystal phase Y as Ys Y AlPOqJDF 1181 709 562 1096 681 534 1025 632 AlAsO4-I 1089 630 498 962 555 450 920 520Fig.2 Scanning electron micrograph of AlP0,-JDF 1208 J. Mater. Chem., 1996, 6(7), 1207-1210 frequencies of the AlP0,-JDF skeletal vibration bands are higher than those for the A1As04-1 vibration bands by ca. 70-100 cm -'. According to eqn. ( 1); T,, T, =P, As the radius of the As atom is larger than that of P atom and the electronegativity of the As atom is smaller than that of P atom, which results in the As-0 bond being less strong than the P-0 bond i.e.fAs-o<fP-o, and the atomic mass of the As atom is larger than that of the P atom, resulting in pAs-O'>h-Oo, so vP-O'vAs-O* According to ref. 16 and comparing the IR spectrum of AlP0,-JDF with that of AlAsO,-l, the bands of the template EAN are assigned in Table 3.The bands of EAN are similar to those of free EAN.17 The characteristic -(CH,), -in-plane rocking vibration band is at 740 cm-', which is very weak in the TR spectrum of AlP0,-JDF, and it is too weak to be observed in that of AlAs0,-1. *'Al, 31Pand I3CMAS NMR Fig.4 shows the experimental 27Al MAS NMR spectrum of as-synthesized AlP0,-JDF. The peaks centred at 6 ca. 31.9 and ca. -4.9 correspond to the two types of A1 atoms. For open framework aluminophosphates with occluded amines, tetrahedrally coordinated A1 atoms gave MAS NMR signals at chemical shifts between 6 20 and 50 and octahedrally coordinated A1 atoms gave ones at around or below 6 0.'s-20 Therefore, the signal of the as-synthesized AlP0,-JDF at 6 3 1.9 corresponds to tetrahedrally coordinated A1 and the signal at 6 -4.9 to octahedral Al.This assignment corresponds with the 27Al MAS NMR results for A1As04-1 and that of the single-crystal structural analysis.21 The 27Al MAS NMR results also show that the template, EAN, has the same sites in both Table 3 Assignment of the IR bonds of the EAN template AlPO4-JDF AlAsO4-1 mode band intensity' band intensity 'IN -H 3400 vw 3402 W "0-H 3 165 S 3163 S "C ~ H 2953 m 2952 m 4-H (in-plane) 1609 S 1609 S (out-of-plane) 1510 S 1510 S dO-H (in-plane) "C -N 1462 984 m m 1462 980 m m b'c -0 885 W 87 1 W -(CH,P 740 vw 'vw =very weak, w =weak, m =medium, s =strong. Band of charac-teristic -(CH,), -in-plane rocking vibration.31.9 I i n a I I 1 I 100 50 0 -50 -100 6 Fig. 4 "A1 MAS NMR spectrum of AlP0,-JDF AlP0,-JDF and AlAs0,- 1, i.e. the four-coordinated A1 shares four oxygen atoms with four adjacent P atoms and the six- coordinate A1 not only shares four oxygen atoms with four adjacent P atoms but also is double bridged with another equivalent A1 atom by two oxygen atoms or nitrogen atoms of EAN molecules located in two eight-membered ring chan- nels. Because of the different bond strengths of P-0 and As-0, the peaks of the as-synthesized AlP0,-JDF are at lower field than those of AlAsO,-l, nearly 6 ca. 9.5 and ca. 6.6, respectively. The 31PMAS NMR spectrum (Fig. 5) of the as-synthesized AlP0,-JDF exhibits two distinct lines located at 6 ca.-13.8 and ca. -30.6 with an intensity ratio of 1 :1. The structure of the as-synthesized AlP0,-JDF molecular sieve with occluded template is shown in Fig. 6. Owing to the presence of template HOCH,CH,NH,, two different P sites are present in the AlP0,-JDF structure: one is due to P(a) and P(b) linked with two six-coordinate A1 and one four- coordinate A1 (only coordinated A1 in the plane are considered because the out-of-plane A1 is the same for both of the two P sites), the other corresponds to P(c) and P(d) linked to one six-coordinate A1 and two four-coordinate Al. Because the symmetry of P(a) and P(b) is altered more than that of P(c) and P(d) comparing with external H$O, (85 mass%), the peak at 6 -30.6 arises from P(a) and P(b) and the one at 6 -13.8 is assigned to P(c) and P(d).The as-synthesized AlP0,- JDF only gives one 13C MAS NMR signal at 6 ca. 52.9, showing that the template is in the channel. TG and DTA Thermogravimetry (Fig. 7A) indicates that the total mass loss is 24.7 mass% from 281 to 698"C, corresponding to the -13*8 I I -30.6 I I I I 1 100 50 0 -50 -100 6 Fig. 5 31PMAS NMR spectrum of AlP04-JDF Fig. 6 Structure of as-synthesized AlP0,-JDF molecular sieve with occluded template. Two different P sites are present in the AlP04- JDF structure: one is due to P(a) and P(b) joined with two six- coordinate A1 and one four-coordinate A1 (only coordinated A1 atoms in the plane are considered because the out-of-plane A1 is the same for both of the two P sites); the other corresponds to P(c) and P(d) joined to one six-coordinate A1 and two four-coordinate Al. J.Muter. Chern., 1996, 6(7), 1207-1210 1209 50.0 B I endo It 1 1nnl 11 I I 1 V." 30.0 190.0 350.0 510.0 670.0 830.0 TI% Fig.7 A, TG (a) and DTG (b) curves, and B, DTA curve for AlPO4- JDF desorption of template EAN The first step is from 281 to 400 "C, and the progress of mass loss is very fast, corresponding to the destruction of EAN Meanwhile, a small amount of carbon produced by the decomposition of EAN aggregates at the sample The second step is from 400 to 698"C, and the mass loss proceeds more slowly, corresponding to the oxidation of the aggregated carbon DTA (Fig 7B) also shows this progress the endothermic peak at 384°C corresponds to the first process and the broad exothermic peak at 590°C corre-sponds to the second process This result is in good agreement with the XRD result Note that AlP0,-JDF retains its structure after calcination at 300°C It collapses to an amorphous form above 400 "C Conclusion AlP0,-JDF is a new member of the family of aluminophos- phates based on microporous materials, and it has been successfully synthesized from predominantly non-aqueous solutions The results of investigating the crystallization of AlP0,-JDF are summarized and compared with those of AlAsO,-l 31P MAS NMR spectroscopy shows that the P atoms have two types of sites because of the presence of the template HOCH2CH,NH2 one type of P atoms joins with two six-coordinate A1 and one four-coordinate A1 (only in- plane coordinated A1 are considered because the out-of-plane A1 are the same for both the two types of P sites), the other type of P atoms are attached to one six-coordinate and two four-coordinate A1 The most important feature of this study is that the non- aqueous synthesis technique is very important for the synthesis of microporous materials We believe that other known and unknown structural microporous materials will be synthesized by this technique, which will contribute greatly to the under- standing of the nature and chemistry of microproducts We thank the National Natural Science Foundation of China and the Ph D Studentship Foundation of the State Education Commission for financial support References 1 S T Wilson, B M Lok and E M Flanigen, US Pat, 1982, 4310440 2 E M Flanigen, B M Lok, R L Patton and S T Wilson, Pure Appl Chem, 1986,58,1351 3 M E Davis, C Saldarriaga, C Montes, J Garces and C Crowder, Nature (London), 1988,331,698 4 J Felsche, S Luger and C Baerlocher, Zeolites, 1986,6, 367 5 G Ferraris, D W Jones and J Yerkess, Z Kzstallogr, 1972, 135, 240 6 D H Olson, J Phys Chem, 1970,74,2758 7 M L Costenoble, W J Mortier and J B Uytterhoeven, J Chem Soc Faradav Trans I, 1976,72,1877 8 B M Lok, C A Messina, R L Patton, R T Gajek, T R Cannan and E M Flanigen, J Am Chem Soc , 1984,106,6092 9 J J Pluth and J V Smith, J Phys Chem, 1989,93,6516 10 J M Bennett and B K Markus, Proc Int Symp on Innovations in Zeolite Materials Sciences, Belgium, 1987, ed P J Grobet, W J Mortier, E F Vansant and G Schulz-Ekloff, 1988, p 269 11 Q Gao, S Li and R Xu, J Chem Soc Chem Commun, 1994.1465 12 G Yang, L Li, J Chen and R Xu, J Chem Soc Chern Commun, 1989,810 13 Collection of Simulated XRD POM ders Patterns for Zeolites Zeolites, 1990,10,I344S 14 E M Flanigen, H Khatami and H A Szymanski, Adv Chem Ser ACS, 1971,101,201 15 J Chen, Ph D Thesis, Jilin University, Changchun, 1989 16 Qinghan Jin, Instrument Analysis, Jilin University, 1990 17 C J Pouchert, The Aldrich Library of Infrared Spectra, Aldrich Chemical Company, 1981. p 197 18 D Muller, E Jahn, B Fahke, G Ladwig and U Haubenriisstr, Zeolites, 1985, 5, 53 19 I P Appleyard, R K Harris and F R Frich, Zeolrtes, 1986,6,428 20 C S Blackwell and R 1 Pation, J Phys Chem, 1988,92,3965 21 J Chen, Ph D Thesis, Jilin University, Changchun, 1989 22 C Reichardt, Solcents and Solvent Effects in Organic Chemistry, Verlag Chemie, Weinheim, 2nd edn ,ch 2, 1988 Paper 51069985, Received 23rd October, 1995 1210 J Mater Chem, 1996, 6(7), 1207-1210